JP2004118973A - Magnetic recording medium and manufacturing method for magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve corrosion resistance, travelling property, and durability of a magnetic recording medium having high recording density. <P>SOLUTION: In a magnetic recording medium having at least a magnetic layer 2 consisting of ferromagnetic metal films on a non-magnetic support 1; a protecting layer 3 on the magnetic layer; an underlayer layer between the magnetic layer 2 and the non-magnetic support 1; and a rear side underlayer 5 on a main plane opposite to the magnetic layer forming plane side, the protection layer 3, the underlayer layer 4, and the rear side under layer 5 are formed as at least any of silicon nitride film, silicon oxide film, silicon oxide nitride film, silicon carbide film, and carbon film containing hydrogen by a catalyst chemical vapor phase growth method by applying contact-thermal decomposition to gaseous starting material using a heat catalyst medium, or it is formed as at least any of silicon nitride film, silicon oxide film, silicon oxide nitride film, silicon carbide film, and carbon film containing hydrogen by a plasma CVD method by heating a permanent magnet or an electromagnet part of a cool cathode ion source. <P>COPYRIGHT: (C)2004,JPO

Description

【００７１】
【表２】

【００７２】
【表３】

【００７３】
【表４】

【００７４】
【表５】

【００７５】
【表６】

【００７６】
【表７】

【００７７】
上記実施例Ａ１〜実施例Ａ４１、比較例Ａ１〜比較例Ａ１７の磁気テープについて、スチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）の測定を行った。
ここで、スチル耐久性、およびシャトル耐久性の測定には、デッキに市販のソニー製デジタルビデオ（ＶＸ−１０００）を改造し、ＭＲヘッドを搭載したものを用いた。
【００７８】
スチル耐久性の測定においては、０℃０％ＲＨの環境下でデジタルビデオカセットに１０分長の磁気テープを組み込み１分間記録した後、巻き戻しを行い３０秒再生した時点で一時停止を行い出力をモニタリングし、一時停止した初期の出力に対し、出力が半分（−６ｄＢ）となるまでの時間を測定した。
スチル耐久性の評価については、◎が６０分以上、○が３０分以上６０分未満、△が１５分以上３０分未満、×が１５分未満とした。
【００７９】
シャトル耐久性の測定においては、４０℃８０％ＲＨの環境下で、デジタルビデオカセットに６０分長の磁気テープを組み込み、１分間記録した後巻き戻しを行い１分間再生し、その時の出力を初期出力とした。その後、１回だけ全長記録を行い、繰り返し再生を行い、出力をモニタリングしながら走行させ、上記の初期出力に対し、出力が半分（−６ｄＢ）となるまでの走行繰り返し回数（パス回数）を測定した。
シャトル耐久性の評価については、◎が１００パス以上、○が８０パス以上１００パス未満、△が５０パス以上８０パス未満、×が５０パス未満とした。
【００８０】
ＳＯ_２ガス雰囲気中における錆発生については、磁気テープをＳＯ_２ガス１ｐｐｍ、５０℃８０％ＲＨの環境下で１０時間保存し、その保存前後での磁化量の劣化率を評価した。
磁化劣化率は、〔（保存前の磁化量−保存後の磁化量）／保存前の磁化量〕×１００により求めるものとした。
ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）の評価については、◎が５％以下、○が５％よりも大きく１０％以下、△が１０％よりも大きく１５％以下、×が１５％よりも大きい、とした。
【００８１】
高温高湿環境下における錆発生（磁化劣化率）については、磁気テープを６５℃９０％ＲＨ中に６日間保存し、その保存前後における磁化量の劣化率を評価した。
磁化劣化率は、〔（保存前の磁化量−保存後の磁化量）／保存前の磁化量〕×１００により求めるものとした。
高温高湿環境下における錆発生（磁化劣化率）の評価については、◎が５％以下、○が５％よりも大きく１０％以下、△が１０％よりも大きく１５％以下、×が１５％よりも大きい、とした。
【００８２】
下記〔表８〕に、スチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）のそれぞれの評価のランク分けを示す。
【００８３】
【表８】

【００８４】
上記実施例Ａ１〜実施例Ａ４１、比較例Ａ１〜比較例Ａ１７の磁気テープの評価結果を下記〔表９〕〜〔表１４〕に示す。
【００８５】
【表９】

【００８６】
【表１０】

【００８７】
【表１１】

【００８８】
【表１２】

【００８９】
【表１３】

【００９０】
【表１４】

【００９１】
上記表９〜表１１に示すように、保護層３、下地層４、裏面下地層５の少なくともいずれかが、ダイヤモンドライクカーボン膜、ＳｉＯ膜、ＳｉＮ膜、ＳｉＣ膜、ＳｉＯＮ膜として形成されてなり、磁性層２の膜厚を２０〜１００ｎｍ、保護層３の膜厚を４〜２５ｎｍ、下地層４の膜厚を４〜１００ｎｍ、裏面下地層５の膜厚を４〜１００ｎｍとした実施例Ａ１〜実施例Ａ４１の磁気テープについては、いずれもスチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）のそれぞれの評価が○以上で、実用上極めて良好な結果が得られた。
【００９２】
一方、表１２に示すように、比較例Ａ１の磁気テープは磁性層２の膜厚が２０ｎｍ未満と薄くしたことにより、特にシャトル耐久性と高温高湿環境下における錆発生（磁化劣化率）の評価が劣り、実用上望ましい特性が得られなかった。
【００９３】
表１２に示すように、比較例Ａ２〜比較例Ａ４の磁気テープは、保護層３の膜厚が４ｎｍ未満と薄すぎ、スチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）のすべての評価が劣り、実用上望ましい特性が得られなかった。
【００９４】
表１２に示すように、比較例Ａ５〜比較例Ａ７の磁気テープは、保護層３が２５ｎｍよりも厚く形成したものであるが、これらはスチル耐久性、繰り返し走行耐久性（シャトル耐久性）の評価が劣り、実用上望ましい特性が得られなかった。
【００９５】
表１３に示すように、比較例Ａ８〜比較例Ａ１２の磁気テープは、下地層４を４ｎｍよりも薄く形成したものであるが、これらはＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、および高温高湿環境下における錆発生（磁化劣化率）の評価が劣り、実用上望ましい特性が得られなかった。
【００９６】
表１４に示すように、比較例Ａ１３〜比較例Ａ１７の磁気テープは、裏面下地層５を４ｎｍよりも薄く形成したものであるが、これらは、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、および高温高湿環境下における錆発生（磁化劣化率）の評価が劣り、実用上望ましい特性が得られなかった。
【００９７】
上述したように、保護層３、下地層４および裏面下地層５の少なくともいずれかを、加熱触媒体を用いて原料ガスを接触熱分解して触媒化学気相成長法によってダイヤモンドライクカーボン膜、ＳｉＯ膜、ＳｉＮ膜、ＳｉＣ膜、ＳｉＯＮ膜のうちのいずれかに形成し、磁性層２の膜厚を２０〜１００ｎｍ、保護層３の膜厚を４〜２５ｎｍ、下地層４の膜厚を４〜１００ｎｍ、裏面下地層５の膜厚を４〜１００ｎｍとすることによって、スチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）のいずれの評価についても良好な結果が得られた。
【００９８】
次に、保護層３、下地層４および裏面下地層５を、冷陰極イオンソースを用いたプラズマＣＶＤ法によって形成した磁気記録媒体の具体例について説明する。
【００９９】
〔実施例Ｂ１〕
先ず、非磁性支持体１として、膜厚６μｍｍのポリエチレンテレフタレート（ＰＥＴ）フィルムを用意した。この非磁性支持体１の磁性層形成面側に、膜厚２０ｎｍのＳｉＮよりなる下地層４、膜厚２０ｎｍのＣｏ−ＣｏＯよりなる磁性層２、および膜厚１０ｎｍのダイヤモンドライクカーボン膜よりなる保護層３を順次形成し、磁性層形成面側とは反対側の主面に、膜厚２０ｎｍのＳｉＮよりなる裏面下地層５を形成した。
【０１００】
〔実施例Ｂ２〕〜〔実施例Ｂ４１〕、〔比較例Ｂ１〕〜〔比較例Ｂ１７〕
磁性層２、保護層３、下地層４、および裏面下地層５の構成と膜厚を変え、その他の条件は上記実施例Ｂ１と同様にして磁気記録媒体を作製した。
【０１０１】
保護層３、下地層３、および裏面下地層５の、冷陰極イオンソースを用いたＣＶＤ法における成膜条件を下記〔表１５〕に示す。
また実施例Ｂ１〜実施例Ｂ４１、比較例Ｂ１〜比較例Ｂ１７の磁気記録媒体の構成を下記〔表１６〕〜〔表２１〕に示す。
【０１０２】
【表１５】

【０１０３】
【表１６】

【０１０４】
【表１７】

【０１０５】
【表１８】

【０１０６】
【表１９】

【０１０７】
【表２０】

【０１０８】
【表２１】

【０１０９】
上記実施例Ｂ１〜実施例Ｂ４１、比較例Ｂ１〜比較例Ｂ１７の磁気テープについて、スチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）の測定を行った。
ここで、スチル耐久性、およびシャトル耐久性の測定には、デッキに市販のソニー製デジタルビデオ（ＶＸ−１０００）を改造し、ＭＲヘッドを搭載したものを用いた。
【０１１０】
スチル耐久性の測定においては、０℃０％ＲＨの環境下でデジタルビデオカセットに１０分長の磁気テープを組み込み１分間記録した後、巻き戻しを行い３０秒再生した時点で一時停止を行い出力をモニタリングし、一時停止した初期の出力に対し、出力が半分（−６ｄＢ）となるまでの時間を測定した。
スチル耐久性の評価については、◎が６０分以上、○が３０分以上６０分未満、△が１５分以上３０分未満、×が１５分未満とした。
【０１１１】
シャトル耐久性の測定においては、４０℃８０％ＲＨの環境下で、デジタルビデオカセットに６０分長の磁気テープを組み込み、１分間記録した後巻き戻しを行い１分間再生し、その時の出力を初期出力とした。その後、１回だけ全長記録を行い、繰り返し再生を行い、出力をモニタリングしながら走行させ、上記の初期出力に対し、出力が半分（−６ｄＢ）となるまでの走行繰り返し回数（パス回数）を測定した。
シャトル耐久性の評価については、◎が１００パス以上、○が８０パス以上１００パス未満、△が５０パス以上８０パス未満、×が５０パス未満とした。
【０１１２】
ＳＯ_２ガス雰囲気中における錆発生については、磁気テープをＳＯ_２ガス１ｐｐｍ、５０℃８０％ＲＨの環境下で１０時間保存し、その保存前後での磁化量の劣化率を評価した。
磁化劣化率は、〔（保存前の磁化量−保存後の磁化量）／保存前の磁化量〕×１００により求めるものとした。
ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）の評価については、◎が５％以下、○が５％よりも大きく１０％以下、△が１０％よりも大きく１５％以下、×が１５％よりも大きい、とした。
【０１１３】
高温高湿環境下における錆発生（磁化劣化率）については、磁気テープを６５℃９０％ＲＨ中に６日間保存し、その保存前後における磁化量の劣化率を評価した。
磁化劣化率は、〔（保存前の磁化量−保存後の磁化量）／保存前の磁化量〕×１００により求めるものとした。
高温高湿環境下における錆発生（磁化劣化率）の評価については、◎が５％以下、○が５％よりも大きく１０％以下、△が１０％よりも大きく１５％以下、×が１５％よりも大きい、とした。
【０１１４】
下記〔表２２〕に、スチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）のそれぞれの評価のランク分けを示す。
【０１１５】
【表２２】

【０１１６】
上記実施例Ｂ１〜実施例Ｂ４１、比較例Ｂ１〜比較例Ｂ１７の磁気テープの評価結果を下記〔表２３〕〜〔表２８〕に示す。
【０１１７】
【表２３】

【０１１８】
【表２４】

【０１１９】
【表２５】

【０１２０】
【表２６】

【０１２１】
【表２７】

【０１２２】
【表２８】

【０１２３】
上記表２３〜表２５に示すように、保護層３、下地層４、裏面下地層５の少なくともいずれかが、ダイヤモンドライクカーボン膜（炭素膜および水素含有炭素膜）、ＳｉＯ膜、ＳｉＮ膜、ＳｉＣ膜、ＳｉＯＮ膜として形成されてなり、磁性層２の膜厚を２０〜１００ｎｍ、保護層３の膜厚を４〜２５ｎｍ、下地層４の膜厚を４〜１００ｎｍ、裏面下地層５の膜厚を４〜１００ｎｍとした実施例Ｂ１〜実施例Ｂ４１の磁気テープについては、いずれもスチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）のそれぞれの評価が○以上で、実用上極めて良好な結果が得られた。
【０１２４】
一方、表２６に示すように、比較例Ｂ１の磁気テープは、磁性層２の膜厚が２０ｎｍ未満と薄くしたことにより、特にシャトル耐久性と高温高湿環境下における錆発生（磁化劣化率）の評価が劣り、実用上望ましい特性が得られなかった。
【０１２５】
表２６に示すように、比較例Ｂ２〜比較例Ｂ４の磁気テープは、保護層３の膜厚が４ｎｍ未満と薄すぎ、スチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）のすべての評価が劣り、実用上望ましい特性が得られなかった。
【０１２６】
表２６に示すように、比較例Ｂ５〜比較例Ｂ７の磁気テープは、保護層３を２５ｎｍよりも厚く形成したものであるが、これらはスチル耐久性、繰り返し走行耐久性（シャトル耐久性）の評価が劣り、実用上望ましい特性が得られなかった。
【０１２７】
表２７に示すように、比較例Ｂ８〜比較例Ｂ１２の磁気テープは、下地層４を４ｎｍよりも薄く形成したものであるが、これらはＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、および高温高湿環境下における錆発生（磁化劣化率）の評価が劣り、実用上望ましい特性が得られなかった。
【０１２８】
表２８に示すように、比較例Ｂ１３〜比較例Ｂ１７の磁気テープは、裏面下地層５を４ｎｍよりも薄く形成したものであるが、これらは、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、および高温高湿環境下における錆発生（磁化劣化率）の評価が劣り、実用上望ましい特性が得られなかった。
【０１２９】
上述したように、保護層３、下地層４および裏面下地層５の少なくともいずれかを、冷陰極イオンソースを用いたプラズマＣＶＤ法により、窒化珪素膜、酸化珪素膜、酸化窒化珪素膜、ダイヤモンドライクカーボン膜（炭化珪素膜、炭素膜および水素含有炭素膜）のいずれかに形成し、磁性層２の膜厚を２０〜１００ｎｍ、保護層３の膜厚を４〜２５ｎｍ、下地層４の膜厚を４〜１００ｎｍ、裏面下地層５の膜厚を４〜１００ｎｍとしたことによって、スチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）について、実用上良好な評価が得られた。
【０１３０】
次に、比較例として、下地層４および裏面下地層５を形成せず、保護層３をＣＶＤ法によってダイヤモンドライクカーボン膜として形成した磁気記録媒体の具体例について説明する。
【０１３１】
〔比較例Ｃ１〕
先ず、非磁性支持体１として、膜厚６μｍｍのポリエチレンテレフタレート（ＰＥＴ）フィルムを用意した。この非磁性支持体１の一主面に、膜厚２０ｎｍのＣｏ−ＣｏＯよりなる磁性層２、および膜厚１０ｎｍのダイヤモンドライクカーボン膜よりなる保護層３を順次形成した。
【０１３２】
〔比較例Ｃ２〕、〔比較例Ｃ３〕
磁性層２の膜厚を変え、その他の条件は上記比較例Ｃ１と同様にして磁気記録媒体を作製した。
【０１３３】
保護層３のＣＶＤ法における成膜条件を下記〔表２９〕に示す。
また、比較例Ｃ１〜比較例Ｃ３の磁気記録媒体の構成を下記〔表３０〕に示す。
【０１３４】
【表２９】

【０１３５】
【表３０】

【０１３６】
上記比較例Ｃ１〜比較例Ｃ３の磁気テープについて、スチル耐久性、繰り返し走行耐久性（シャトル耐久性）、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）の測定を行った。
スチル耐久性、およびシャトル耐久性の測定には、デッキに市販のソニー製デジタルビデオ（ＶＸ−１０００）を改造し、ＭＲヘッドを搭載したものを用いた。
測定方法および評価基準については、上述した各実施例と同様とした。
【０１３７】
上記比較例Ｃ１〜比較例Ｃ３の磁気テープの評価結果を下記〔表３１〕に示す。
【０１３８】
【表３１】

【０１３９】
表３１に示すように、比較例Ｃ１〜比較例Ｃ３の磁気テープは、下地層４および裏面下地層５を形成しない構成としたことにより、特にスチル耐久性、ＳＯ_２ガス雰囲気中における錆発生（磁化劣化率）、高温高湿環境下における錆発生（磁化劣化率）の評価について、実用上良好な評価が得られなかった。
【０１４０】
【発明の効果】
本発明によれば、保護層、下地層、あるいは裏面下地層の少なくともいずれかを、加熱触媒体を用いて原料ガスを接触熱分解して、触媒化学気相成長法により、窒化珪素膜、炭化珪素膜、炭素膜および水素含有炭素膜のいずれかに形成したことにより、磁性層を極めて薄層に形成した場合においても、充分に耐食性、走行性および耐久性の向上が図られ、磁気抵抗効果型磁気ヘッド（ＭＲヘッド）を用いた磁気記録システム用として好適な磁気記録媒体が得られた。
【０１４１】
また、本発明によれば、保護層、下地層、あるいは裏面下地層の少なくともいずれかを、冷陰極イオンソースを用いたプラズマＣＶＤ法によって、窒化珪素膜、酸化珪素膜、酸化窒化珪素膜、炭化珪素膜、炭素膜および水素含有炭素膜のいずれかに形成したことにより、磁性層を極めて薄層に形成した場合においても、充分に耐食性、走行性、および耐久性の向上が図られ、磁気抵抗効果型磁気ヘッド（ＭＲヘッド）を用いた磁気記録システム用として好適な磁気記録媒体が得られた。
【図面の簡単な説明】
【図１】本発明の磁気記録媒体の一例の概略構成図を示す。
【図２】磁性層を形成する真空蒸着装置の概略構成図を示す。
【図３】本発明の磁気記録媒体を構成する保護層、下地層、裏面下地層を形成する触媒化学気相成長装置の概略構成図を示す。
【図４】本発明の磁気記録媒体の他の一例の概略構成図を示す。
【図５】本発明の磁気記録媒体の他の一例の概略構成図を示す。
【図６】本発明の磁気記録媒体を構成する保護層、下地層、裏面下地層を形成する冷陰極イオンソースによるＣＶＤ装置の概略構成図を示す。
【図７】本発明の磁気記録媒体の一例の概略構成図を示す。
【符号の説明】
１……非磁性支持体、２……磁性層、３……保護層、４……下地層、５……裏面下地層、６……バックコート層、７……潤滑剤層、１０，２０，３０……磁気記録媒体、４０……真空蒸着装置、４１，４２……排気口、４３……真空室、４４……送りロール、４５……巻き取りロール、４６……冷却キャン、４７，４８……ガイドロール、４９……ルツボ、５０……金属磁性材料、５１……電子銃、５２……シャッタ、５４……酸素ガス導入管、６０……触媒化学気相成長装置、６１……真空排気系、６２……真空室、６３……送りロール、６４……巻き取りロール、６５……被処理体、６６……冷却キャン、６７，６８……ガイドロール、６９……フード、７０……カタライザ、７１……交流電源、７２……原料供給シャワーヘッド、７３……ガス導入パイプ、７４……ビューポート、７５……赤外線温度計、８０……冷陰極イオンソースによるＣＶＤ装置、８１……真空排気系、８２……真空室、８３……送りロール、８４……巻き取りロール、８５……被処理体、８６……冷却キャン、８７，８８……ガイドロール、８９……フード、９０……冷陰極イオンソース、９１……アノード、９２……磁石、９３……直流電源、９４……原料ガス導入口、９５……原料ガス導入パイプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic recording medium having a magnetic layer formed by a vacuum thin film forming technique and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, as a magnetic tape such as an audio tape or a video tape, a powdery magnetic material such as an oxide magnetic powder or an alloy magnetic powder is coated on a long non-magnetic support by using a vinyl chloride-vinyl acetate copolymer, polyester. So-called coating-type magnetic recording media, which are produced by applying a magnetic paint dispersed in an organic binder such as a resin, a urethane resin, or a polyurethane resin, have been widely used.
[0003]
On the other hand, with the increasing demand for high-density magnetic recording, metal magnetic materials such as Co-Ni-based alloys, Co-Cr-based alloys, and Co-O have been used for plating and vacuum thin film forming means (vacuum evaporation and sputtering). A so-called metal thin-film type magnetic recording medium which is directly adhered to a non-magnetic support such as a polyester film, a polyamide, a polyimide film or the like by a conventional method or an ion plating method has been proposed and put into practical use.
[0004]
This metal magnetic thin film type magnetic recording medium not only has excellent coercive force and squareness ratio, and has excellent electromagnetic conversion characteristics at short wavelengths. Has a number of advantages, such as that the thickness loss of the magnetic material is extremely small, and that the binder (binder), which is a nonmagnetic material, is not mixed into the magnetic layer, so that the packing density of the magnetic material can be increased. I have.
[0005]
Also, in order to improve the electromagnetic conversion characteristics of this type of magnetic recording medium and to obtain a larger output, so-called oblique deposition in which a magnetic layer is deposited obliquely has been proposed. It has been put to practical use as a magnetic recording medium for milli-Hi-8 format, DV format) or professional video (DVCAM).
[0006]
In the metal thin film type magnetic recording medium as described above, a protective layer is usually formed on a magnetic layer, a lubricant layer is formed on an outermost layer, and a non-magnetic The back layer is formed on the surface of the support opposite to the side on which the magnetic layer is formed.
[0007]
In the case of a metal thin film type magnetic recording medium, the surface tends to be smoothed in order to reduce the spacing loss in response to the increase in density, but when the magnetic layer surface becomes smooth, the contact area with the magnetic head is reduced. As the size increases, the frictional force increases, and the shear stress generated in the magnetic layer increases. To protect the magnetic layer from such severe sliding conditions, it is important to form a protective layer.
[0008]
Further, it is desirable that a lubricant is applied to the outermost layer of the magnetic recording medium to form a lubricant layer so that sliding with a magnetic head and a guide roll is smooth, and durability and running performance are improved.
[0009]
In addition, by forming a back layer, the electric resistance of the surface of the non-magnetic support is lowered to prevent running failure due to charging, the durability of the non-magnetic support is improved, and the occurrence of scratches during use is prevented, Further, effects such as reduction of friction between the magnetic tapes can be obtained, and the running property and durability of the magnetic tape can be improved.
[0010]
In many cases, a carbon film or a hydrogen-containing carbon film is used as the protective layer, and a sputtering method or a plasma CVD method is applied as a forming method thereof.
In the plasma CVD method, a current is caused to flow from a guide roll in contact with a magnetic layer, and a voltage is applied between the magnetic layer (ferromagnetic metal thin film) as an electrode and a mesh-shaped electrode in a CVD reaction tube. A protective layer is formed by a method in which a discharge is generated to decompose the hydrocarbon-based film-forming gas introduced into the reaction tube by glow discharge and deposit the gas on the magnetic layer.
[0011]
[Problems to be solved by the invention]
By the way, polyester is mainly used as a non-magnetic support (base film) for a magnetic recording medium.
[0012]
However, a configuration in which a polyester film having a thickness of about 4 to 15 μm is used as the nonmagnetic support, a specific matte surface and a filler surface are formed on the surface, and a magnetic layer made of an extremely thin ferromagnetic metal thin film is formed. When the protective layer is formed by the above-described conventional plasma CVD method in the magnetic recording medium described above, the magnetic layer (ferromagnetic metal thin film) is used as an electrode. As the value increases, it is difficult to apply a voltage between the ferromagnetic metal thin film as an electrode and the mesh electrode in the CVD reaction tube. In particular, when the thickness of the ferromagnetic metal thin film is 100 nm or less, such a problem becomes remarkable.
[0013]
Further, since it is impossible to form a carbon film and a hydrogen-containing carbon film directly on the non-magnetic support polyester film as an insulator by this CVD method, a magnetic tape for high-density recording is produced. In such a case, there has been a problem that sufficient characteristics cannot be improved with respect to running properties, corrosion resistance, and durability.
[0014]
In view of the above problems, the present inventor has proposed a high-density magnetic recording medium having a magnetic layer made of a ferromagnetic metal thin film having a thickness of 20 to 100 nm, which is particularly suitable for a system using an MR head. , Running performance, and durability.
[0015]
[Means for Solving the Problems]
The magnetic recording medium of the present invention has a magnetic layer comprising a ferromagnetic metal thin film on a non-magnetic support, a protective layer on the magnetic layer, an underlayer and a magnetic layer between the magnetic layer and the non-magnetic support. The main surface opposite to the surface side has at least one of the backing underlayers. It is assumed to be one of a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film formed by decomposition and catalytic chemical vapor deposition.
[0016]
Further, the magnetic recording medium of the present invention has a magnetic layer made of a ferromagnetic metal thin film on a non-magnetic support, a protective layer on the magnetic layer, an underlayer between the magnetic layer and the non-magnetic support, The main surface opposite to the magnetic layer forming surface has at least one of a back surface underlayer, and the protective layer, the underlayer, and the back surface underlayer are formed on the discharge side surface of the cold cathode ion source. Is heated, and any one of a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film formed by a plasma CVD method is used.
[0017]
The method for producing a magnetic recording medium according to the present invention comprises a magnetic layer comprising a ferromagnetic metal thin film on a non-magnetic support, a protective layer on the magnetic layer, and a lower layer between the magnetic layer and the non-magnetic support. A method of manufacturing a magnetic recording medium comprising at least one of a backing layer on a main surface opposite to a ground layer and a magnetic layer forming surface side, the method comprising: a protective layer, a base layer, and a backing layer. In the forming step, while the nonmagnetic support is cooled, the raw material gas is subjected to catalytic pyrolysis using a heating catalyst, and the silicon nitride film, the silicon oxide film, the silicon oxynitride film, At least one of a silicon film, a carbon film, and a hydrogen-containing carbon film is formed.
[0018]
Further, the method for producing a magnetic recording medium of the present invention has a magnetic layer comprising a ferromagnetic metal thin film on a non-magnetic support, a protective layer on the magnetic layer, and a magnetic layer between the magnetic layer and the non-magnetic support. An underlayer, a method for manufacturing a magnetic recording medium having at least one of a back surface underlayer on a main surface opposite to a magnetic layer formation surface side, wherein the protective layer, the underlayer, and the back surface underlayer are formed. Heats the discharge-side surface of a cold cathode ion source and forms at least one of a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film by a plasma CVD method. Shall be.
[0019]
According to the present invention, a high-density magnetic recording medium having a magnetic layer made of a ferromagnetic metal thin film having a thickness of 20 to 100 nm, which is particularly suitable for a system using an MR head, relates to corrosion resistance, running properties, and durability. Improvement is achieved.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
A specific embodiment of the magnetic recording medium of the present invention will be described, but the present invention is not limited to the following example.
FIG. 1 shows a schematic sectional view of an example of the magnetic recording medium 10 of the present invention.
In the magnetic recording medium 10, a magnetic layer 2 made of a ferromagnetic metal thin film and a protective layer 3 are sequentially formed on a long non-magnetic support 1, and a main surface opposite to a surface on which the magnetic layer 2 is formed. Has a configuration in which a back coat layer 6 is formed.
[0021]
As a material for forming the nonmagnetic support (base film) 1, a polyester-based material is mainly used. As the polyester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytetramethylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, polyethylene 2,6-naphthalene dicarboxylate, polyethylene-p-oxy Benzoate and the like. In particular, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are preferred, and homopolyesters and copolyesters can be applied to these polyesters.
The non-magnetic support 1 has a thickness of about 4 to 15 μm. In order to improve the durability and running property of the magnetic recording medium 10 and the handling at the time of forming a magnetic tape, a binder resin, a filler and Fine irregularities may be added to the surface by a paint containing a surfactant or the like, or mechanical strength may be increased.
Examples of the binder resin include an aqueous polyester resin, an aqueous acrylic resin, an aqueous polyurethane resin and the like, and examples of the filler include particles made of a heat-resistant polymer, particles of silicon dioxide, calcium carbonate and the like.
[0022]
In addition to the above-described methods, a method of artificially forming irregularities on the nonmagnetic support 1 by a lithography technique, or an island-like structure of a metal, an inorganic compound, or an organic polymer by a plating or vacuum thin film forming technique May be used to form minute projections on the surface.
[0023]
The magnetic layer 2 is made of Co, CoNi, a vapor deposition layer made of these oxides, or a CoCrTa, CoCrPt, CoCrPtTa, CoPtSiO layer on a Cr layer. ₂ , CoPtB—O sputtered layers are formed, or these sputtered layers are formed alone without forming a Cr layer. The coercive force of the magnetic layer is 100 to 250 kA / m.
[0024]
Next, as an example of a process of forming the magnetic layer 2, a case where a magnetic layer is formed by vacuum deposition will be described using a continuous winding type vacuum deposition apparatus 40 as shown in FIG.
In the vacuum deposition apparatus 40, a feed roll 44, a take-up roll 45, and a feed roll 45 are placed in a vacuum chamber 43 that is evacuated from exhaust ports 41 and 42 provided in a head and a lower portion, respectively, and has a vacuum state. The elongate non-magnetic support 1 runs sequentially from the feed roll 44 to the take-up roll 45.
[0025]
A cooling can 46 is provided in the middle of the travel of the non-magnetic support 1 from the feed roll 44 to the take-up roll 45. The cooling can 46 is provided so as to pull out the nonmagnetic support 1 downward in the drawing, and is configured to rotate at a constant speed. Note that a cooling device (not shown) is provided inside the cooling can 46 so as to suppress deformation and the like of the nonmagnetic support 1 due to a rise in temperature.
Guide rolls 47 and 48 are provided between the feed roll 44 and the cooling can 46 and between the cooling can 46 and the take-up roll 45, respectively. To make it run smoothly.
[0026]
In the vacuum chamber 43, a crucible 49 is provided below the cooling can 46, and the crucible 49 is filled with a metallic magnetic material 50. On the other hand, an electron gun 51 for heating and evaporating the metallic magnetic material 50 filled in the crucible 49 is attached to the side wall of the vacuum chamber 43. The electron gun 51 is disposed at a position where the emitted electron beam X irradiates the metal magnetic material 50 in the crucible 49. Then, the metal magnetic material 50 evaporated by the electron gun 51 is formed as a magnetic layer 2 on the non-magnetic support 1 running on the peripheral surface of the cooling can 46.
[0027]
Further, a shutter 52 is provided between the cooling can 46 and the crucible 49 and near the cooling can 46. The shutter 52 is provided so as to cover a predetermined area of the non-magnetic support 1 running at a constant speed on the peripheral surface of the cooling can 46. The film is deposited obliquely within the range of the angle. Further, the oxygen gas is supplied to the surface of the non-magnetic support 1 through the oxygen gas inlet 54 provided through the side wall of the vacuum chamber 43 to improve the magnetic properties, durability and weather resistance. ing.
[0028]
The magnetic recording medium of the present invention is applied to a recording / reproducing apparatus having an MR head. In order to reduce noise and improve C / N, the magnetic layer 2 is formed as an extremely thin layer. It is preferable that the film is formed to a thickness of 20 to 100 nm.
[0029]
The protective layer 3 on the magnetic layer 2 is formed of a silicon nitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film formed by catalytic chemical vapor deposition by catalytically decomposing a raw material gas using a heated catalyst. It shall consist of at least one. Hereinafter, a method for forming the protective layer 3 will be specifically described with reference to the drawings.
[0030]
FIG. 3 shows a schematic configuration diagram of a catalytic chemical vapor deposition apparatus 60 for forming the protective layer 3.
In the catalytic chemical vapor deposition apparatus 60, a feed roll 63 and a take-up roll 64, which rotate at a constant speed, are placed in a vacuum chamber 62 in which a high vacuum state is formed by a vacuum exhaust system 61 provided on a side surface. The workpiece 65 in which the magnetic layer 2 is formed on the non-magnetic support 1 as described above runs sequentially from the feed roll 63 to the take-up roll 64.
[0031]
A cooling can 66 is provided in the middle of the movement of the object 65 from the feed roll 63 to the take-up roll 64. The cooling can 66 is provided so as to pull out the object to be processed 65 downward in the figure, and is configured to rotate at a constant speed in the direction of arrow A in the figure. Further, a cooling mechanism (not shown) is provided inside the cooling can 66 to suppress deformation and the like of the processing target 65 due to a rise in temperature.
Accordingly, the processing target 65 is sequentially sent out from the feed roll 63, passes through the peripheral surface of the cooling can 66, and is taken up by the take-up roll 64. In addition, guide rolls 67 and 68 are provided between the feed roll 63 and the cooling can 66 and between the cooling can 66 and the take-up roll, respectively. It has been made to be.
[0032]
A hood 69 made of stainless steel is provided in the vacuum chamber 62, and a catalyzer 70 provided with a wire made of a high melting point metal such as molybdenum, tantalum, or tungsten serving as a catalyst is provided inside the hood 69. I have. Both ends of the wire of the catalyzer 70 are connected to an AC power supply 71 provided outside the vacuum chamber 62 via an introduction terminal having an insulated structure.
[0033]
The catalyzer 70 receives current supply from the AC power supply 71 and generates heat at 1500 ° C. or higher. A shower head 72 for introducing a source gas is provided below the catalyzer 70. The shower head 72 has a box-like structure made of hollow stainless steel, and has a large number of holes having a diameter of 1 mm formed on the upper surface. A gas introduction pipe 73 is connected to the lower surface of the shower head 72. I have.
The gas introduction pipe 73 is provided so as to penetrate the bottom of the hood 69 and the bottom wall of the vacuum chamber 62 so that a source gas can be supplied.
[0034]
In addition, a viewport 74 in which quartz glass is installed diagonally downward is provided through the side portion 69 of the hood and the side wall portion of the vacuum chamber 62, and the temperature of the catalyzer 70 inside the hood 69 is measured by an infrared thermometer 75. It has a structure that can be monitored.
[0035]
In the catalytic chemical vapor deposition apparatus 60 shown in FIG. 3, the inside of the vacuum chamber 62 is first set to a high vacuum state, and then a predetermined raw material gas is supplied from a gas introduction pipe 73 through a shower head 72 by an AC power supply 71. It is supplied to the catalizer 70 which has been heated and has been heated to 1500 ° C. or more. As a result, the source gas is subjected to catalytic pyrolysis, and a silicon nitride film, a silicon carbide film, a carbon film, a hydrogen-containing carbon film, and the like are formed on the processing target 65 in accordance with the source gas.
In the magnetic recording medium of the present invention, the protective layer 3 was formed with a thickness of 4 nm to 25 nm.
[0036]
On the protective layer 3 formed as described above, for example, an arbitrary perfluoropolyether-based lubricant is applied to form a lubricant layer (not shown) in order to improve running properties. Is also good.
[0037]
On the side opposite to the surface on which the magnetic layer 2 is formed, a back coat layer 6 having a thickness of about 0.2 to 0.7 μm is formed for the purpose of improving running properties and preventing electrification.
The back coat layer 6 is prepared by dispersing solid particles such as an inorganic pigment in a binder, kneading the dispersion with an organic solvent corresponding to the type of the binder to prepare a coating for the back coat layer, Formed on the back side of the substrate.
[0038]
As described above, the protective layer 3 is subjected to catalytic pyrolysis of a raw material gas using a heated catalyst, and any of a silicon nitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film is formed by catalytic chemical vapor deposition. By forming the magnetic layer 2, even when the magnetic layer 2 is formed as an extremely thin layer, the corrosion resistance, running properties, and durability are sufficiently improved, and a magnetoresistive head (MR head) is used. It can be made suitable as a magnetic recording medium for a magnetic recording system.
Here, the MR head is a read-only magnetic head that detects a signal from a magnetic recording medium using a magnetoresistance effect. In general, an MR head has higher sensitivity and a higher reproduction output than an inductive magnetic head that performs recording and reproduction using electromagnetic induction, and thus is suitable for a magnetic recording medium for high-density recording.
[0039]
[Second embodiment]
Next, another example of the magnetic recording medium of the present invention will be described with reference to the drawings.
In the magnetic recording medium 20 shown in FIG. 4, an underlayer 4 and a magnetic layer 2 made of a ferromagnetic metal thin film are sequentially formed on one main surface of the nonmagnetic support 1, and the magnetic layer 2 is formed on the opposite side to the magnetic layer forming surface side. Has a configuration in which a back coat layer 6 is formed.
The same non-magnetic support as the non-magnetic support of the magnetic recording medium 10 shown in FIG. 1 is applied to the non-magnetic support 1, and the magnetic layer 2 is also formed by a vapor deposition method or a sputtering method using the vacuum vapor deposition apparatus 40 shown in FIG. Thus, the configuration is the same as that of the first embodiment. The back coat layer 6 can also be formed by the same method as in the case of the magnetic recording medium of FIG.
[0040]
The underlayer 4 is formed in the same manner as the protective layer 3 constituting the magnetic recording medium 10 shown in FIG. That is, the underlying layer 4 is formed by applying the catalytic chemical vapor deposition apparatus 60 shown in FIG. It is made of at least one of a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film. The underlayer 4 is formed to a thickness of 4 to 100 nm.
[0041]
As described above, the base layer 4 between the magnetic layer 2 and the non-magnetic support 1 is subjected to catalytic pyrolysis of a raw material gas using a heated catalyst, and a silicon nitride film, Even when the magnetic layer 2 is formed as an extremely thin layer, it has sufficient corrosion resistance and running properties even when formed on any one of a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film. In addition, the durability is improved, and the magnetic recording medium can be suitably used as a magnetic recording medium for a magnetic recording system using a magnetoresistive head (MR head).
[0042]
[Third Embodiment]
Next, another example of the magnetic recording medium of the present invention will be described with reference to the drawings.
The magnetic recording medium 30 shown in FIG. 5 has a magnetic layer 2 made of a ferromagnetic metal thin film on a non-magnetic support 1, and has a main surface opposite to the magnetic layer 2 forming side of the non-magnetic support 1. It has a configuration in which a back underlayer 5 is formed.
The non-magnetic support 1 may be the same as the non-magnetic support of the magnetic recording medium 10 shown in FIG. 1, and the magnetic layer 2 may be formed by a vapor deposition method or a sputtering method using the vacuum vapor deposition device 40 shown in FIG. Thereby, it can be formed in the same configuration as in the first embodiment. The back coat layer 6 can also be formed by the same method as in the case of the magnetic recording medium of FIG.
[0043]
The back underlayer 5 is formed by the same method as the protective layer 3 constituting the magnetic recording medium 10 shown in FIG. That is, the rear underlayer 5 is a silicon nitride film formed by catalytic chemical vapor deposition by catalytically pyrolyzing a raw material gas using a heated catalyst by applying the catalytic chemical vapor deposition apparatus 60 shown in FIG. It is made of at least one of a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film. The back underlayer 5 is formed to a thickness of 4 to 100 nm.
[0044]
As described above, the backside underlayer 5 between the nonmagnetic support 1 and the backcoat layer 6 is subjected to catalytic pyrolysis of a raw material gas using a heating catalyst, and is subjected to catalytic chemical vapor deposition to produce silicon nitride. Since the magnetic layer 2 is formed on any one of a film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film, even when the magnetic layer 2 is formed as an extremely thin layer, it has sufficient corrosion resistance and running properties. As a result, the performance and durability are improved, and the magnetic recording medium can be made suitable as a magnetic recording medium for a magnetic recording system using a magnetoresistive magnetic head (MR head).
[0045]
Note that it is desirable to form a diamond-like carbon layer on the magnetic layers 2 of the magnetic recording media 20 and 30 shown in FIGS. 4 and 5 in order to ensure good running durability and corrosion resistance.
The diamond-like carbon layer can be formed by, for example, a CVD method using a plasma CVD (Chemical Vapor Deposition) continuous film forming apparatus. As the CVD method, any of conventionally known methods such as a mesh electrode DC plasma method, an electron beam excited plasma source method, a cold cathode ion source method, an ionization vapor deposition method, and a catalytic CVD method can be used.
As the carbon compound used in the CVD method, any of conventionally known materials such as a hydrocarbon compound, a ketone compound, and an alcohol compound can be used. At the time of plasma generation, Ar and H are used as gases for promoting the differentiation of the carbon compound. ₂ Etc. may be introduced.
[0046]
In the magnetic recording media 10, 20, and 30 shown in the first to third embodiments, for example, an arbitrary perfluoropolyether-based lubricant is applied to the outermost surface in order to improve running properties. A configuration in which a lubricant layer is formed as a result may be adopted.
[0047]
[Fourth Embodiment]
Next, another example of the magnetic recording medium of the present invention will be described.
The magnetic recording medium in this example has the same configuration as the magnetic recording medium in the above-described first embodiment. That is, a magnetic layer 2 made of a ferromagnetic metal thin film and a protective layer 3 are sequentially formed on a long non-magnetic support 1, and a back coat layer 6 is formed on a main surface opposite to a surface on which the magnetic layer 2 is formed. Is formed.
[0048]
The same non-magnetic support 1 as in the above-described example can be applied, and the magnetic layer 2 can be formed by the vapor deposition method using the vacuum vapor deposition apparatus 40 shown in FIG. The back coat layer 6 can be formed in the same manner, and the back coat layer 6 can be formed by the same method as that of the magnetic recording medium shown in FIG.
[0049]
In this example, the protective layer 3 is formed on at least one of a silicon nitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film by a plasma CVD method using a cold cathode ion source. Hereinafter, a method for forming the protective layer 3 will be specifically described with reference to the drawings.
[0050]
FIG. 6 shows a schematic configuration diagram of a CVD apparatus 80 using a cold cathode ion source.
In the CVD apparatus 80, a feed roll 83 and a take-up roll 84, which rotate at a constant speed, are provided in a vacuum chamber 82, the inside of which is brought into a high vacuum state by a vacuum exhaust system 81 provided on the side surface. As described above, the object 85 having the magnetic layer 2 formed on the non-magnetic support 1 runs from the feed roll 83 to the take-up roll 84 sequentially.
[0051]
A cooling can 86 is provided in the middle of the movement of the object 85 from the feed roll 83 to the take-up roll 84. The cooling can 86 is provided so as to pull out the object to be processed 85 downward in the figure, and is configured to rotate at a constant speed in the direction of arrow B in the figure. Further, a cooling mechanism (not shown) is provided inside the cooling can 86 to suppress deformation or the like of the processing target 85 due to a rise in temperature.
Therefore, the target object 85 is sequentially sent out from the feed roll 83, passes through the peripheral surface of the cooling can 86, and is taken up by the take-up roll 84. Note that guide rolls 87 and 88 are provided between the feed roll 83 and the cooling can 86 and between the cooling can 86 and the take-up roll 84, respectively. It is made to run.
[0052]
A hood 89 made of stainless steel is provided in the vacuum chamber 82, and a cold cathode ion source 90 is provided inside the hood 89. An anode 91 and a magnet 92 are provided inside the cold cathode ion source 90. The magnet 92 may be a permanent magnet or an electromagnet. A DC power supply 93 is provided outside the vacuum chamber 82, and the anode 91 is connected to the DC power supply 93 via an insulated introduction terminal.
[0053]
A source gas introduction pipe 95 is connected to the cold cathode ion source 90 from a source gas introduction hole 94 penetrating the bottom.
The source gas introduction pipe 95 is provided through the bottom of the hood 89 and the bottom wall of the vacuum chamber 82 so that the source gas can be supplied.
[0054]
In the CVD apparatus 80 using the cold cathode ion source shown in FIG. 6, first, the inside of the vacuum chamber 82 is set to a high vacuum state, and then a predetermined source gas is supplied into the cold cathode ion source 90 from the gas introduction pipe 95.
Subsequently, a predetermined voltage is applied by using the cooling can 86 serving as a cathode and the anode 91, and a discharge is generated between them. Then, the raw material gas introduced into the cold cathode ion source 90 is decomposed by this discharge, and a predetermined layer is formed on the target object 85 running on the peripheral surface of the cooling can 86. This protective layer 3 is formed to a thickness of 4 nm to 25 nm.
[0055]
On the protective layer 3 formed by the plasma CVD method using the cold cathode ion source as described above, for example, an arbitrary perfluoropolyether-based lubricant is applied to improve the running property by applying a lubricant. A layer (not shown) may be formed.
[0056]
On the side opposite to the side on which the magnetic layer 2 is formed, a back coat layer 6 is formed for the purpose of improving runnability and preventing electrification.
The back coat layer 6 preferably has a thickness of about 0.2 to 0.7 μm. The back coat layer 6 is prepared by dispersing solid particles such as an inorganic pigment in a binder, kneading the dispersion with an organic solvent corresponding to the type of the binder to prepare a coating for the back coat layer, Formed on the back side of the substrate.
[0057]
In the magnetic recording medium manufactured as described above, the protective layer 3 is formed on at least one of a silicon nitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film by a plasma CVD method using a cold cathode ion source. Due to the formation, even when the magnetic layer 2 is formed as an extremely thin layer, the corrosion resistance, running properties, and durability are sufficiently improved, and magnetic recording using a magnetoresistive magnetic head (MR head) is performed. It can be made suitable as a magnetic recording medium for a system.
[0058]
[Fifth Embodiment]
Next, another example of the magnetic recording medium of the present invention will be described with reference to the drawings.
The magnetic recording medium in this example has the same configuration as the magnetic recording medium shown in FIG. 4 and described in the second embodiment. That is, a configuration in which an underlayer 4 and a magnetic layer 2 composed of a ferromagnetic metal thin film are sequentially formed on one main surface of a non-magnetic support 1, and a back coat layer 6 is formed on the side opposite to the side on which the magnetic layer is formed. It is assumed that
The non-magnetic support 1 may be the same as the non-magnetic support of the magnetic recording medium 10 shown in FIG. 1, and the magnetic layer 2 may be formed by a vapor deposition method or a sputtering method using the vacuum vapor deposition device 40 shown in FIG. Accordingly, the configuration can be the same as that of the above-described first embodiment, and the back coat layer 6 can also be formed by the same method as that of the above-described magnetic recording medium.
[0059]
The underlayer 4 can be formed by the same method as the protective layer 3 constituting the magnetic recording medium described in the fourth embodiment. That is, a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a plasma CVD method using a cold cathode ion source are applied by applying the protective layer forming CVD apparatus 80 shown in FIG. It is formed on any of the hydrogen-containing carbon films. The thickness of the underlayer 4 is 4 to 100 nm.
[0060]
As described above, base layer 4 is formed on any of a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film by a plasma CVD method using a cold cathode ion source. As a result, even when the magnetic layer 2 is formed to be extremely thin, the corrosion resistance, running properties, and durability are sufficiently improved, and a magnetic recording system using a magnetoresistive head (MR head) is used. Suitable as a magnetic recording medium for use.
[0061]
[Sixth Embodiment]
Next, another example of the magnetic recording medium of the present invention will be described with reference to the drawings.
The magnetic recording medium in this example has the same configuration as the magnetic recording medium 30 shown in FIG. 5 and described in the third embodiment.
That is, a structure in which a magnetic layer 2 made of a ferromagnetic metal thin film is provided on a nonmagnetic support 1 and a backing underlayer 5 is formed on a main surface of the nonmagnetic support 1 opposite to a surface on which the magnetic layer 2 is formed. have.
The non-magnetic support 1 may be the same as the non-magnetic support of the magnetic recording medium 10 shown in FIG. 1, and the magnetic layer 2 may be formed by a vapor deposition method or a sputtering method using the vacuum vapor deposition device 40 shown in FIG. Accordingly, the configuration can be the same as that of the above-described first embodiment, and the back coat layer 6 can also be formed by the same method as that of the above-described magnetic recording medium.
[0062]
Further, the back underlayer 5 can be formed by the same method as the protective layer 3 constituting the magnetic recording medium described in the fourth embodiment. That is, a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film are formed by a plasma CVD method using a cold cathode ion source by applying the protective layer forming CVD apparatus 80 shown in FIG. And a hydrogen-containing carbon film. The back underlayer 4 is formed to a thickness of 4 to 100 nm.
[0063]
As described above, the silicon nitride film, the silicon oxide film, the silicon oxynitride film, and the back underlayer 5 between the nonmagnetic support 1 and the back coat layer 6 are formed by a plasma CVD method using a cold cathode ion source. By forming the magnetic layer 2 in any of a silicon carbide film, a carbon film, and a hydrogen-containing carbon film, the corrosion resistance, running properties, and durability are sufficiently improved even when the magnetic layer 2 is formed as an extremely thin layer. It can be suitable as a magnetic recording medium for a magnetic recording system using a magnetoresistive magnetic head (MR head).
[0064]
Note that it is desirable to form a diamond-like carbon layer on the magnetic layers 2 of the magnetic recording media 20 and 30 shown in FIGS. 4 and 5 in order to ensure good running durability and corrosion resistance.
[0065]
In the magnetic recording media shown in the fourth to sixth embodiments, in order to improve running properties, for example, an arbitrary perfluoropolyether-based lubricant is applied to the outermost surface to form a lubricant layer. Is desirably formed.
[0066]
【Example】
Hereinafter, specific examples of the magnetic recording medium of the present invention will be described based on experimental results.
FIG. 7 shows a schematic sectional view of the magnetic recording medium. Although FIG. 7 shows all of the protective layer 3, the underlayer 4, and the back surface underlayer 5, in the following examples, a magnetic recording medium having a configuration in which any of these layers is formed will be described. explain.
[0067]
[Example A1]
First, a polyethylene terephthalate (PET) film having a thickness of 6 μm was prepared as the nonmagnetic support 1. On the side of the nonmagnetic support 1 on which the magnetic layer is formed, an underlayer 4 made of 20 nm thick SiN, a magnetic layer 2 made of 20 nm thick Co—CoO, and a protection made of a 10 nm thick diamond-like carbon film. Layers 3 were sequentially formed, and a backing underlayer 5 of 20 nm thick made of SiN was formed on the main surface opposite to the magnetic layer forming surface side.
[0068]
[Example A2] to [Example A41], [Comparative Example A1] to [Comparative Example A17]
A magnetic recording medium was manufactured in the same manner as in Example A1, except that the configurations and thicknesses of the magnetic layer 2, the protective layer 3, the underlayer 4, and the back underlayer 5 were changed.
[0069]
In Examples A1 to A41 and Comparative Examples A1 to A17, the protective layer 3, the underlayer 4, and the back surface underlayer 5 were each subjected to catalytic pyrolysis of a raw material gas using a heating catalyst. A diamond-like carbon film, a SiO film, a SiN film, a SiC film, or a SiON film was formed by a catalytic chemical vapor deposition method. These film forming conditions are shown in the following [Table 1]. The configurations of the magnetic recording media of Examples A1 to A41 and Comparative Examples A1 to A17 are shown in Tables 2 to 7 below.
[0070]
[Table 1]

[0071]
[Table 2]

[0072]
[Table 3]

[0073]
[Table 4]

[0074]
[Table 5]

[0075]
[Table 6]

[0076]
[Table 7]

[0077]
Regarding the magnetic tapes of Examples A1 to A41 and Comparative Examples A1 to A17, still durability, repeated running durability (shuttle durability), SO ₂ Rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high temperature and high humidity environment were measured.
Here, for the measurement of the still durability and the shuttle durability, a commercially available digital video (VX-1000) made by Sony and modified with a MR head was used for the deck.
[0078]
In the measurement of still durability, a 10-minute magnetic tape was inserted into a digital video cassette in an environment of 0 ° C. and 0% RH, recorded for 1 minute, then rewound, paused when reproduced for 30 seconds, and output. Was monitored, and the time until the output became half (-6 dB) of the initial output that was temporarily stopped was measured.
Regarding the evaluation of still durability, ◎ was 60 minutes or more, ○ was 30 minutes or more and less than 60 minutes, Δ was 15 minutes or more and less than 30 minutes, and X was less than 15 minutes.
[0079]
In the measurement of shuttle durability, a magnetic tape of 60 minutes length was incorporated into a digital video cassette in an environment of 40 ° C. and 80% RH, recorded for 1 minute, rewound and played back for 1 minute, and the output at that time was initialized. Output. After that, full-length recording is performed only once, repetitive reproduction is performed, the vehicle is run while monitoring the output, and the number of running repetitions (the number of passes) is measured until the output becomes half (-6 dB) of the above initial output. did.
Regarding the evaluation of shuttle durability, ◎ was 100 or more passes, ○ was 80 or more and less than 100 passes, Δ was 50 or more and less than 80 passes, and × was less than 50 passes.
[0080]
SO ₂ For rust generation in gas atmosphere, use magnetic tape ₂ It was stored for 10 hours in an environment of 1 ppm of gas and 50 ° C. and 80% RH, and the deterioration rate of the magnetization amount before and after the storage was evaluated.
The magnetization deterioration rate was determined by [(magnetization amount before storage−magnetization amount after storage) / magnetization amount before storage] × 100.
SO ₂ Regarding the evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere, ◎ is 5% or less, ○ is more than 5% and 10% or less, Δ is more than 10% and 15% or less, and X is more than 15%. It was big.
[0081]
Regarding rust generation (magnetization deterioration rate) under a high temperature and high humidity environment, the magnetic tape was stored at 65 ° C. and 90% RH for 6 days, and the deterioration rate of the magnetization amount before and after the storage was evaluated.
The magnetization deterioration rate was determined by [(magnetization amount before storage−magnetization amount after storage) / magnetization amount before storage] × 100.
Regarding the evaluation of rust generation (magnetization deterioration rate) in a high-temperature and high-humidity environment, ◎ is 5% or less, ○ is more than 5% and 10% or less, Δ is more than 10% and 15% or less, and X is 15%. Larger than
[0082]
Table 8 below shows the still durability, repeated running durability (shuttle durability), SO ₂ The ranking of each evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high temperature and high humidity environment is shown.
[0083]
[Table 8]

[0084]
The evaluation results of the magnetic tapes of Examples A1 to A41 and Comparative Examples A1 to A17 are shown in Tables 9 to 14 below.
[0085]
[Table 9]

[0086]
[Table 10]

[0087]
[Table 11]

[0088]
[Table 12]

[0089]
[Table 13]

[0090]
[Table 14]

[0091]
As shown in Tables 9 to 11, at least one of the protective layer 3, the underlayer 4, and the back underlayer 5 is formed as a diamond-like carbon film, a SiO film, a SiN film, a SiC film, or a SiON film. Example A1 in which the thickness of the magnetic layer 2 was 20 to 100 nm, the thickness of the protective layer 3 was 4 to 25 nm, the thickness of the underlayer 4 was 4 to 100 nm, and the thickness of the back surface underlayer 5 was 4 to 100 nm. -For the magnetic tapes of Example A41, still durability, repeated running durability (shuttle durability), SO ₂ The evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high-temperature, high-humidity environment were respectively ○ or more, and extremely good results in practical use were obtained.
[0092]
On the other hand, as shown in Table 12, in the magnetic tape of Comparative Example A1, the thickness of the magnetic layer 2 was reduced to less than 20 nm, and particularly, shuttle durability and rust generation (magnetization deterioration rate) under a high temperature and high humidity environment were reduced. The evaluation was inferior and practically desirable characteristics could not be obtained.
[0093]
As shown in Table 12, in the magnetic tapes of Comparative Examples A2 to A4, the protective layer 3 was too thin with a thickness of less than 4 nm, still durability, repetitive running durability (shuttle durability), SO ₂ All evaluations of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high-temperature and high-humidity environment were poor, and practically desirable characteristics could not be obtained.
[0094]
As shown in Table 12, in the magnetic tapes of Comparative Examples A5 to A7, the protective layer 3 was formed to be thicker than 25 nm, and these layers had still durability and repeated running durability (shuttle durability). The evaluation was inferior and practically desirable characteristics could not be obtained.
[0095]
As shown in Table 13, the magnetic tapes of Comparative Examples A8 to A12 had the underlayer 4 formed to be thinner than 4 nm. ₂ The evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high-temperature, high-humidity environment was poor, and practically desirable characteristics could not be obtained.
[0096]
As shown in Table 14, the magnetic tapes of Comparative Examples A13 to A17 had the back underlayer 5 formed to be thinner than 4 nm. ₂ The evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high-temperature, high-humidity environment was poor, and practically desirable characteristics could not be obtained.
[0097]
As described above, at least one of the protective layer 3, the underlayer 4, and the back underlayer 5 is subjected to catalytic pyrolysis of a raw material gas using a heating catalyst, and a diamond-like carbon film or SiO Film, a SiN film, a SiC film, or a SiON film, the magnetic layer 2 has a thickness of 20 to 100 nm, the protective layer 3 has a thickness of 4 to 25 nm, and the underlayer 4 has a thickness of 4 to 25 nm. By setting the thickness of the backing underlayer 5 to 100 nm and the thickness of the backing layer 5 to 4 to 100 nm, still durability, repeated running durability (shuttle durability), SO ₂ Good results were obtained for both evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high temperature and high humidity environment.
[0098]
Next, a specific example of a magnetic recording medium in which the protective layer 3, the underlayer 4, and the backside underlayer 5 are formed by a plasma CVD method using a cold cathode ion source will be described.
[0099]
[Example B1]
First, a polyethylene terephthalate (PET) film having a thickness of 6 μm was prepared as the nonmagnetic support 1. On the side of the nonmagnetic support 1 on which the magnetic layer is formed, an underlayer 4 made of 20 nm thick SiN, a magnetic layer 2 made of 20 nm thick Co—CoO, and a protection made of a 10 nm thick diamond-like carbon film. Layers 3 were sequentially formed, and a backing underlayer 5 of 20 nm thick made of SiN was formed on the main surface opposite to the magnetic layer forming surface side.
[0100]
[Example B2] to [Example B41], [Comparative Example B1] to [Comparative Example B17]
A magnetic recording medium was manufactured in the same manner as in Example B1 except that the configuration and thickness of the magnetic layer 2, the protective layer 3, the underlayer 4, and the back underlayer 5 were changed.
[0101]
The following Table 15 shows film forming conditions for the protective layer 3, the underlayer 3, and the backside underlayer 5 in a CVD method using a cold cathode ion source.
The structures of the magnetic recording media of Examples B1 to B41 and Comparative Examples B1 to B17 are shown in Tables 16 to 21 below.
[0102]
[Table 15]

[0103]
[Table 16]

[0104]
[Table 17]

[0105]
[Table 18]

[0106]
[Table 19]

[0107]
[Table 20]

[0108]
[Table 21]

[0109]
For the magnetic tapes of Examples B1 to B41 and Comparative Examples B1 to B17, still durability, repetitive running durability (shuttle durability), SO ₂ Rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high temperature and high humidity environment were measured.
Here, for the measurement of the still durability and the shuttle durability, a commercially available digital video (VX-1000) made by Sony and modified with a MR head was used for the deck.
[0110]
In the measurement of still durability, a 10-minute magnetic tape was inserted into a digital video cassette in an environment of 0 ° C. and 0% RH, recorded for 1 minute, then rewound, paused when reproduced for 30 seconds, and output. Was monitored, and the time until the output became half (-6 dB) of the initial output that was temporarily stopped was measured.
Regarding the evaluation of still durability, ◎ was 60 minutes or more, ○ was 30 minutes or more and less than 60 minutes, Δ was 15 minutes or more and less than 30 minutes, and X was less than 15 minutes.
[0111]
In the measurement of shuttle durability, a magnetic tape of 60 minutes length was incorporated into a digital video cassette in an environment of 40 ° C. and 80% RH, recorded for 1 minute, rewound and played back for 1 minute, and the output at that time was initialized. Output. After that, full-length recording is performed only once, repetitive reproduction is performed, the vehicle is run while monitoring the output, and the number of running repetitions (the number of passes) is measured until the output becomes half (-6 dB) of the above initial output. did.
Regarding the evaluation of shuttle durability, ◎ was 100 or more passes, ○ was 80 or more and less than 100 passes, Δ was 50 or more and less than 80 passes, and × was less than 50 passes.
[0112]
SO ₂ For rust generation in gas atmosphere, use magnetic tape ₂ It was stored for 10 hours in an environment of 1 ppm of gas and 50 ° C. and 80% RH, and the deterioration rate of the magnetization amount before and after the storage was evaluated.
The magnetization deterioration rate was determined by [(magnetization amount before storage−magnetization amount after storage) / magnetization amount before storage] × 100.
SO ₂ Regarding the evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere, ◎ is 5% or less, ○ is more than 5% and 10% or less, Δ is more than 10% and 15% or less, and X is more than 15%. It was big.
[0113]
Regarding rust generation (magnetization deterioration rate) under a high temperature and high humidity environment, the magnetic tape was stored at 65 ° C. and 90% RH for 6 days, and the deterioration rate of the magnetization amount before and after the storage was evaluated.
The magnetization deterioration rate was determined by [(magnetization amount before storage−magnetization amount after storage) / magnetization amount before storage] × 100.
Regarding the evaluation of rust generation (magnetization deterioration rate) in a high-temperature and high-humidity environment, ◎ is 5% or less, ○ is more than 5% and 10% or less, Δ is more than 10% and 15% or less, and X is 15%. Larger than
[0114]
Table 22 below shows still durability, repeated running durability (shuttle durability), SO ₂ The ranking of each evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high temperature and high humidity environment is shown.
[0115]
[Table 22]

[0116]
The evaluation results of the magnetic tapes of Examples B1 to B41 and Comparative Examples B1 to B17 are shown in Tables 23 to 28 below.
[0117]
[Table 23]

[0118]
[Table 24]

[0119]
[Table 25]

[0120]
[Table 26]

[0121]
[Table 27]

[0122]
[Table 28]

[0123]
As shown in Tables 23 to 25, at least one of the protective layer 3, the underlayer 4, and the back underlayer 5 is made of a diamond-like carbon film (a carbon film and a hydrogen-containing carbon film), a SiO film, a SiN film, and a SiC film. The magnetic layer 2 has a thickness of 20 to 100 nm, the protective layer 3 has a thickness of 4 to 25 nm, the underlayer 4 has a thickness of 4 to 100 nm, and the back surface underlayer 5 has a thickness of 20 to 100 nm. In each of the magnetic tapes of Examples B1 to B41 in which the magnetic tape was set to 4 to 100 nm, still durability, repeated running durability (shuttle durability), SO ₂ The evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high-temperature, high-humidity environment were respectively ○ or more, and extremely good results in practical use were obtained.
[0124]
On the other hand, as shown in Table 26, in the magnetic tape of Comparative Example B1, since the thickness of the magnetic layer 2 was reduced to less than 20 nm, particularly, shuttle durability and rust generation (magnetization deterioration rate) under a high-temperature, high-humidity environment. Was poor, and practically desirable characteristics could not be obtained.
[0125]
As shown in Table 26, in the magnetic tapes of Comparative Example B2 to Comparative Example B4, the thickness of the protective layer 3 was too thin as less than 4 nm, still durability, repetitive running durability (shuttle durability), SO ₂ All evaluations of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high-temperature and high-humidity environment were poor, and practically desirable characteristics could not be obtained.
[0126]
As shown in Table 26, in the magnetic tapes of Comparative Examples B5 to B7, the protective layer 3 was formed to be thicker than 25 nm, and these layers had still durability and repeated running durability (shuttle durability). The evaluation was inferior and practically desirable characteristics could not be obtained.
[0127]
As shown in Table 27, in the magnetic tapes of Comparative Examples B8 to B12, the underlayer 4 was formed thinner than 4 nm. ₂ The evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high-temperature, high-humidity environment was poor, and practically desirable characteristics could not be obtained.
[0128]
As shown in Table 28, in the magnetic tapes of Comparative Examples B13 to B17, the back underlayer 5 was formed thinner than 4 nm. ₂ The evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high-temperature, high-humidity environment was poor, and practically desirable characteristics could not be obtained.
[0129]
As described above, at least one of the protective layer 3, the underlayer 4, and the back surface underlayer 5 is formed by a plasma CVD method using a cold cathode ion source by a silicon nitride film, a silicon oxide film, a silicon oxynitride film, and a diamond-like film. It is formed on any one of carbon films (silicon carbide film, carbon film and hydrogen-containing carbon film), the thickness of the magnetic layer 2 is 20 to 100 nm, the thickness of the protective layer 3 is 4 to 25 nm, and the thickness of the underlayer 4 Is 4 to 100 nm and the thickness of the back surface underlayer 5 is 4 to 100 nm, so that still durability, repetitive running durability (shuttle durability), SO ₂ Practical good evaluations were obtained for rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high temperature and high humidity environment.
[0130]
Next, as a comparative example, a specific example of a magnetic recording medium in which the protective layer 3 is formed as a diamond-like carbon film by the CVD method without forming the underlayer 4 and the back surface underlayer 5 will be described.
[0131]
[Comparative Example C1]
First, a polyethylene terephthalate (PET) film having a thickness of 6 μm was prepared as the nonmagnetic support 1. On one main surface of the nonmagnetic support 1, a magnetic layer 2 made of Co—CoO and having a thickness of 20 nm, and a protective layer 3 made of a diamond-like carbon film having a thickness of 10 nm were sequentially formed.
[0132]
[Comparative Example C2], [Comparative Example C3]
A magnetic recording medium was manufactured in the same manner as in Comparative Example C1 except that the thickness of the magnetic layer 2 was changed.
[0133]
The film forming conditions of the protective layer 3 in the CVD method are shown in [Table 29] below.
Table 30 below shows the configurations of the magnetic recording media of Comparative Examples C1 to C3.
[0134]
[Table 29]

[0135]
[Table 30]

[0136]
For the magnetic tapes of Comparative Examples C1 to C3, still durability, repeated running durability (shuttle durability), SO ₂ Rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high temperature and high humidity environment were measured.
For the measurement of still durability and shuttle durability, a commercially available Sony digital video (VX-1000) was remodeled into a deck and an MR head was used.
The measurement method and the evaluation criteria were the same as those in the above-described embodiments.
[0137]
The evaluation results of the magnetic tapes of Comparative Examples C1 to C3 are shown in [Table 31] below.
[0138]
[Table 31]

[0139]
As shown in Table 31, the magnetic tapes of Comparative Example C1 to Comparative Example C3 had a configuration in which the underlayer 4 and the backside underlayer 5 were not formed, so that, in particular, still durability, SO ₂ Regarding the evaluation of rust generation (magnetization deterioration rate) in a gas atmosphere and rust generation (magnetization deterioration rate) in a high-temperature and high-humidity environment, no favorable evaluation was obtained in practice.
[0140]
【The invention's effect】
According to the present invention, at least one of the protective layer, the underlayer, and the backside underlayer is subjected to catalytic pyrolysis of a raw material gas using a heating catalyst, and the silicon nitride film and the carbonized By forming the magnetic layer on any of a silicon film, a carbon film, and a hydrogen-containing carbon film, even when the magnetic layer is formed as an extremely thin layer, the corrosion resistance, running properties, and durability are sufficiently improved, and the magnetoresistance effect is improved. A magnetic recording medium suitable for a magnetic recording system using a magnetic head (MR head) was obtained.
[0141]
Further, according to the present invention, at least one of the protective layer, the underlayer, and the backside underlayer is formed by a plasma CVD method using a cold cathode ion source by a silicon nitride film, a silicon oxide film, a silicon oxynitride film, By forming the magnetic layer on any of a silicon film, a carbon film, and a hydrogen-containing carbon film, even when the magnetic layer is formed as an extremely thin layer, the corrosion resistance, the running property, and the durability are sufficiently improved, and the magnetoresistance is improved. A magnetic recording medium suitable for a magnetic recording system using an effect type magnetic head (MR head) was obtained.
[Brief description of the drawings]
FIG. 1 shows a schematic configuration diagram of an example of a magnetic recording medium of the present invention.
FIG. 2 shows a schematic configuration diagram of a vacuum evaporation apparatus for forming a magnetic layer.
FIG. 3 is a schematic configuration diagram of a catalytic chemical vapor deposition apparatus for forming a protective layer, an underlayer, and a backside underlayer constituting the magnetic recording medium of the present invention.
FIG. 4 is a schematic configuration diagram showing another example of the magnetic recording medium of the present invention.
FIG. 5 shows a schematic configuration diagram of another example of the magnetic recording medium of the present invention.
FIG. 6 is a schematic configuration diagram of a CVD apparatus using a cold cathode ion source for forming a protective layer, an underlayer, and a backside underlayer constituting the magnetic recording medium of the present invention.
FIG. 7 shows a schematic configuration diagram of an example of the magnetic recording medium of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Nonmagnetic support, 2 ... Magnetic layer, 3 ... Protective layer, 4 ... Underlayer, 5 ... Backside underlayer, 6 ... Backcoat layer, 7 ... Lubricant layer, 10, 20 , 30 ... magnetic recording medium, 40 ... vacuum vapor deposition apparatus, 41, 42 ... exhaust port, 43 ... vacuum chamber, 44 ... feed roll, 45 ... winding roll, 46 ... cooling can, 47, 48: guide roll, 49: crucible, 50: metal magnetic material, 51: electron gun, 52: shutter, 54: oxygen gas inlet tube, 60: catalytic chemical vapor deposition apparatus, 61: Vacuum evacuation system, 62 vacuum chamber, 63 feed roll, 64 take-up roll, 65 workpiece, 66 cooling can, 67, 68 guide roll, 69 hood, 70 … Catalyzer, 71… AC power supply, 72… raw material supply shower head, 73 ... gas introduction pipe, 74 ... viewport, 75 ... infrared thermometer, 80 ... CVD apparatus using cold cathode ion source, 81 ... vacuum evacuation system, 82 ... vacuum chamber, 83 ... feed roll, 84 ... ... Winding roll, 85 ... Workpiece, 86 ... Cooling can, 87, 88 ... Guide roll, 89 ... Hood, 90 ... Cold cathode ion source, 91 ... Anode, 92 ... Magnet, 93 … DC power supply, 94… Source gas inlet, 95… Source gas inlet pipe

Claims (22)

A magnetic recording medium having a magnetic layer and a protective layer made of a ferromagnetic metal thin film on a nonmagnetic support,
The protective layer is made of any one of a silicon nitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film formed by catalytic chemical vapor deposition by catalytically pyrolyzing a raw material gas using a heated catalyst. A magnetic recording medium characterized by the following. 2. The magnetic recording medium according to claim 1, wherein said protective layer has a thickness of 4 nm to 25 nm. A magnetic recording medium having a magnetic layer composed of an underlayer and a ferromagnetic metal thin film on a nonmagnetic support,
The underlayer is a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen film formed by catalytic chemical vapor deposition of a raw material gas by catalytic pyrolysis using a heated catalyst. A magnetic recording medium comprising any one of a carbon film containing carbon. 4. The magnetic recording medium according to claim 3, wherein said underlayer has a thickness of 4 to 100 nm. A magnetic recording medium having a magnetic layer made of a ferromagnetic metal thin film on a nonmagnetic support, and having a backing underlayer on a main surface opposite to the magnetic layer forming surface side of the nonmagnetic support,
The backside underlayer is a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film formed by catalytic chemical vapor deposition of a raw material gas by catalytic pyrolysis using a heated catalyst. A magnetic recording medium comprising any one of a hydrogen-containing carbon film. 6. The magnetic recording medium according to claim 5, wherein the thickness of the underlayer is 4 to 100 nm. A magnetic recording medium having a magnetic layer made of a ferromagnetic metal thin film on a non-magnetic support,
A protective layer on the magnetic layer, an underlayer between the non-magnetic support and the magnetic layer, a back surface underlayer on a main surface opposite to the magnetic layer forming surface side, at least one of: A silicon nitride film, a silicon oxide film, a silicon oxynitride film, wherein the protective layer, the underlayer, and the back underlayer are formed by catalytic chemical vapor deposition by catalytically decomposing a raw material gas using a heating catalyst. A magnetic recording medium comprising any one of a film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film. The magnetic layer, Co, CoNi, deposited layer consisting of oxides or CoCrTa on Cr _{layer,, CoCrPt, CoCrPtTa, CoPtSiO 2} , obtained by forming a sputtered layer of CoPtB-O, or the these sputtered layer Consisting of any of those formed alone without forming a Cr layer,
The film thickness of the magnetic layer is 20 to 100 nm, the coercive force of the magnetic layer is 100 to 250 kA / m, and recording and reproduction of signals are performed using a magnetoresistive magnetic head. Item 8. The magnetic recording medium according to any one of items 1 to 7. A method for producing a magnetic recording medium having a magnetic layer and a protective layer made of a ferromagnetic metal thin film on a nonmagnetic support,
In the step of forming the protective layer, a raw material gas is subjected to catalytic pyrolysis using a heated catalyst while cooling the nonmagnetic support, and the silicon nitride film, the silicon carbide film, and the carbon film are formed by catalytic chemical vapor deposition. And forming a hydrogen-containing carbon film. A method for producing a magnetic recording medium having a magnetic layer composed of an underlayer and a ferromagnetic metal thin film on a nonmagnetic support,
In the step of forming the underlayer, while the nonmagnetic support is being cooled, a raw material gas is subjected to catalytic pyrolysis using a heating catalyst, and a silicon nitride film, a silicon oxide film, and an oxide film are formed by catalytic chemical vapor deposition. A method for manufacturing a magnetic recording medium, comprising forming any one of a silicon nitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film. A method for manufacturing a magnetic recording medium comprising: a magnetic layer formed of a ferromagnetic metal thin film on a nonmagnetic support; and a backing underlayer on a main surface of the nonmagnetic support opposite to the magnetic layer forming surface. So,
In the step of forming the backing underlayer, while cooling the nonmagnetic support, a catalytic gas is thermally decomposed using a heating catalyst, and a silicon nitride film, a silicon oxide film, A method for manufacturing a magnetic recording medium, comprising forming any one of a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film. A magnetic recording medium having a magnetic layer and a protective layer on a non-magnetic support,
A magnetic recording medium, wherein the protective layer is a silicon nitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film formed by a plasma CVD method using a cold cathode ion source. The magnetic recording medium according to claim 12, wherein the thickness of the protective layer is 4 nm to 25 nm. A magnetic recording medium having a base layer and a magnetic layer on a non-magnetic support,
The underlayer is formed of any one of a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film formed by a plasma CVD method using a cold cathode ion source. A magnetic recording medium, comprising: The magnetic recording medium according to claim 14, wherein the thickness of the underlayer is 4 to 100 nm. On a non-magnetic support, having a magnetic layer composed of a ferromagnetic metal thin film,
A magnetic recording medium having a backing underlayer on a main surface of the nonmagnetic support opposite to the magnetic layer forming surface,
The back surface underlayer is any one of a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film formed by a plasma CVD method using a cold cathode ion source. A magnetic recording medium characterized by the above-mentioned. 17. The magnetic recording medium according to claim 16, wherein the back underlayer has a thickness of 4 to 100 nm. A magnetic recording medium having a magnetic layer made of a ferromagnetic metal thin film on a non-magnetic support,
A protective layer on the magnetic layer, an underlayer between the non-magnetic support and the magnetic layer, a back surface underlayer on a main surface opposite to the magnetic layer forming surface side, at least one of: A silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and hydrogen, wherein the protective layer, the underlayer, and the back surface underlayer are formed by a plasma CVD method using a cold cathode ion source. A magnetic recording medium comprising any one of a carbon film containing carbon. The magnetic layer, Co, CoNi, deposited layer consisting of oxides or CoCrTa on Cr _{layer,, CoCrPt, CoCrPtTa, CoPtSiO 2} , obtained by forming a sputtered layer of CoPtB-O, or the these sputtered layer It was formed alone without forming a Cr layer,
The magnetic layer has a thickness of 20 to 100 nm, the magnetic layer has a coercive force of 100 to 250 kA / m, and signals are recorded / reproduced using a magnetoresistive head (MR head). The magnetic recording medium according to any one of claims 12 to 18, wherein: On a non-magnetic support, having a magnetic layer composed of a ferromagnetic metal thin film,
A method for producing a magnetic recording medium having a protective layer on the magnetic layer,
In the step of forming the protective layer, the discharge side surface of the cold cathode ion source is heated, and any one of a silicon nitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film is formed by a plasma CVD method. A method for manufacturing a magnetic recording medium. A method for producing a magnetic recording medium having a base layer and a magnetic layer on a non-magnetic support,
In the step of forming the underlayer, the discharge side surface of the cold cathode ion source is heated, and a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon film are formed by a plasma CVD method. A method for manufacturing a magnetic recording medium, characterized by forming any one of the above. On a non-magnetic support, having a magnetic layer composed of a ferromagnetic metal thin film,
A method for producing a magnetic recording medium having a backing underlayer on a main surface of the nonmagnetic support opposite to the magnetic layer forming surface,
In the step of forming the back underlayer, the discharge side surface of the cold cathode ion source is heated, and a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, a carbon film, and a hydrogen-containing carbon are formed by a plasma CVD method. A method for manufacturing a magnetic recording medium, comprising forming one of films.

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